Representatives from Russia, Ukraine, France and Germany met in Paris last Wednesday with the goal of de-escalating the crisis in Ukraine. Russia has now amassed more than 100,000 troops along its border with Ukraine, ramping up tensions in a conflict that has dragged on since 2014. Russia’s key demand is that Ukraine and other countries be blocked from joining Nato – a concession the alliance has firmly ruled out. At the same time, Russian officials continue to insist the troop buildup is just part of military exercises, even as their rhetoric grows more belligerent. The Guardian’s Moscow correspondent, Andrew Roth, walks Michael Safi through some of the possible outcomes should the Russian military invade Ukraine, and explains what kinds of diplomatic off-ramps might be available to tamp down the crisis.